Patent GB-1325776-A (GB)
Title: Synthetic composite filament having a high pilling resistance  and process of manufacturing the same
IPC: D01F8/04
Filed: 1971-01-06
Abstract: 1325776 Synthetic composite filament with pilling resistance TORAY INDUSTRIES Inc 6 Jan 1971 606/71 Heading B5B An "island-in-a-sea'' type composite filament having a high pilling resistance is composed of a sea constituent continuously extending along the longitudinal axis of the composite filament and at least ten island constituents continuously extending in the sea constituent apart from each other along the longitudinal axis, either the sea constituent or the island constituent consists of a pilling resistance imparting polymer as hereinafter defined and a remaining constituent or constituents consists of a fibreforming polymer as hereinafter defined of a composition different from the aforesaid polymer, the ratio X of the content WI in per cent by weight of the island constituents with respect to the content WS in per cent by weight of the sea constituent, X = WI/WS satisfying the relationship 0À5##X#2À0, the composite film has a tenacity T in gram/denier in the range and the ratio Y of the difference between the elongation EF in per cent of the composite filament and the elongation EI in per cent of the island constituents with respect to the elongation EF, Y = |EF-EI|/EF is in the range and preferably 0À25#Y#0À95. The pilling resistance imparting polymers includes amorphous polymers, e.g. vinyl polymers substituted by cyclic groups, such as amorphous polystyne and amorphous polyesters and copolymers of these branched polyamides, polyesters and polyolefins. The composite filament includes either island or sea constituent consisting of the above stated pilling resistance imparting polymer and either sea or island constituent consisting of a fibre-forming synthetic polymer. The fibre forming synthetic polymer is preferably chosen from crystalline polyesters, e.g. polyethylene terephthalate, crystalline polyamides, e.g. nylon 6,66, 10 or 12, crystalline polyolefins, e.g. isotatic polypropylene and crystalline polyethylene. The filament is manufactured by a process involving uniting at least ten of the primary composite streams into an "island-in-asea" type composite stream wherein the sea constituent polymer liquid streams and the island constituent polymer liquid streams are distributed dependently from each other in the incorporated sea constituent polymer liquid stream and the composite stream is then extruded through a spinning orifice forming the filament. When the composite filament is prepared through a melt spinning process it is preferable that the island and sea constituent polymers are selected so that a melt viscosity PI in poise of the island constituent polymer and a melt viscosity PS in poise of the sea constituent polymer are in the relationship In the melt-spinning process the filamentary melt spun through the spinning orifice is preferably cooled for solidification at a gradual cooling condition. For this purpose, the filaments spun through the spinneret are passed through a heat-insulating chimney extending from the spinneret. In this case, the atmospheric temperature in the heat-insulating chimney is preferably set so as to satisfy the relationship: T GS +5#T e #T m +20 wherein T e  is an atmospheric temperature in ‹ C. in the heat-insulating chimney, T GS  is a glass transition temperature in ‹ C. of the sea constituent polymer and T m  is a melt-spinning temperature in ‹ C. The spun filaments are preferably drawn after pre-heating them at a predetermined temperature. The undrawn filaments are subjected to a drawing apparatus wherein a heating zone is disposed between a feeding roll and a drawing roll and a drawing pin is preferably disposed between the feeding roll and the heating zone. The undrawn filaments fed through the feeding roll are wound on the drawing pin, passed through the heating zone while being drawn at a predetermined draw ratio. In this drawing step preferably the temperature T D  in ‹ C. of the heating zone is set so as to satisfy the relationship The spinneret 11 includes a spinning pack 12 and four metal plates 13, 14, 15 and 16. A first passage 18 for flowing the sea constituent polymer B is formed between the second and third plates 14 and 15. An inlet of the first passage 18 is connected to a sea constituent polymer supply source through a passage 24. Numerous second passages 26, for flowing the island constituent polymer A are formed in the first plate 13 and connected with an island constituent polymer source. A partition 17 prevents a contamination of the sea constituent polymer B with the island constituent polymer A. A plurality of these passages 21 are formed from apertures 22 formed in the third plate 15 and pipes 25 attached to the third plate 15. The pipes 25 are connected at lower ends thereof with the upper ends of the apertures 22 respectively. The uniting chambers 20 have a substantially funnel-shaped form and their lower ends are connected to spinning orifices 23. The sea constituent polymer B is distributed into the branched ends 19 through the supply passage 24 and the first passage 18. The island constituent polymer A is also fed into the branched ends 19 through the second passages 26. The several composite streams formed in the branched ends 19 are fed into the uniting chamber 20 through the third passages 21 and united with each other into an "island-in-a-sea" type composite stream which is then extruded.  Fig. 5 shows a further embodiment of the spinneret.